Having trouble pulling vacuum at idle. Need some help!

[Dad's69RR]

I have been trying to get the RR running smooth and I am having trouble getting to build vacuum at idle. I isolated the carb and it is only pulling 3-4 in vac at 700RPM. All accessories are disconnected and I have an Eldebrock 1407 carb. Could it be the intake manifold gasket?

Forgot to mention it is a 383 bored .30 over. According to guy I bought it from it has no miles on it.

 

[eagleone1983]

Did you already spray water around the intake to check for any vacuum leaks? Typical places are at the corners.

 

[Dad's69RR]

Doing that right now!

- - - Updated - - -

Did you already spray water around the intake to check for any vacuum leaks? Typical places are at the corners.

Nothing noticeable! Probably going to have to pull to verify unless you have any other suggestions?

 

[eagleone1983]

I would think if there was a leak that bad that you are only getting 3 - 4" you'd get a spike in RPM with the spray if it were in fact around the intake. Carb base good? All vacuum ports plugged on carb?

 

[brasil]

Ignition.... way retarded ? 3-4 " is nothing.... even a "Killercam" makes more Vacuum...

Did you make a compression test ... and did you check if the cam is dialed in correctly ?

Hope you find out what´s going wrong

Greetings Juergen

 

[dryheat]

X2 with what brasil said.

Where are you pulling your vacuum readings from? Carb or manifold?

 

[brasil]

should be from the driverside port manifold vacuum

 

[Jim's Maxie]

should be from the driverside port manifold vacuum

Actually to get a correct vacuum reading it should be taken directly from the manifold.

 

[Dad's69RR]

X2 with what brasil said.

Where are you pulling your vacuum readings from? Carb or manifold?

Pulling from the manifold! All ports plugged on carb.

I called guy I bought the car from to see if he knew what the cam specs were. He didn't know much but said it has a purple cam and is bigger than what came with it, this worries me! Pulling manifold tonight just to verify how it was put together.

 

[Hemi Rebel]

I cant believe its even running. I would hook that guage to my daily driver to see if its working right.those guages van be kind of delicate. If it was dropped or took a hit it can screw them up

 

[brasil]

the drivers side port of the carb sits under the trottle blade...so this should be o.k for checkin the vacuum... or am I wrong ?

 

[satman72]

I let my wife pull the vacuum!

 

[brasil]

so she´s a mechanic ?? lol

 

[satman72]

Yeah sure! She takes care of my nuts & bolts!!!!!

 

[Dad's69RR]

Yeah sure! She takes care of my nuts & bolts!!!!!

Dang I need to get my wife to give me an Overhaul!

 

[eagleone1983]

Is 700 RPM in park? That is a little low especially if you have an aftermarket cam, they like a little more idle RPM. I've got mine set around 980 RPM in park. I wish you were closer so we could look at this thing together.

 

[Dad's69RR]

Is 700 RPM in park? That is a little low especially if you have an aftermarket cam, they like a little more idle RPM. I've got mine set around 980 RPM in park. I wish you were closer so we could look at this thing together.

Me too! I was hoping this would be one of the easiest portions of the project so I can focus on the items that is going to take me a little longer. I will give an update in a little while after I check my vacuum gauge to something else. Then I will get idle up and see what happens.

 

[charger360]

just for fun what is your ignition timing at idle without vac adv? if you have any kind of cam at all you are going to want to be in the 15 degree range for initial with 34-36 or so total mechanical advance. and eddy carbs don't like low low vacuum like that without some metering rod spring tuning!

 

[Dad's69RR]

just for fun what is your ignition timing at idle without vac adv? if you have any kind of cam at all you are going to want to be in the 15 degree range for initial with 34-36 or so total mechanical advance. and eddy carbs don't like low low vacuum like that without some metering rod spring tuning!

I am about 13 deg so after I put back together I will advance to 15 and see what happens.

 

[charger360]

yeah 2 degrees is not going to get you much more vacuum. you have somthing else going on i think.